On Wednesday, Senate Democrats may avail themselves of the so-called "constitutional option" and make some minor tweaks to the filibuster, the rule that permits a senator or series of senators to speak as long as they want on an issue in an effort to delay or prevent a vote.

If early reports are to be believed, the Democrats, who hold a majority of votes in the Senate, are considering tweaks that would speed up the process of ending a filibuster and make it easier to hold a continuous debate on a bill. Filibusters would still be allowed on all bills that don't go through budget reconciliation, and they would still require 60 votes to break.

The Senate has a long tradition of revising its rules, customs and traditions. In comparison with earlier changes, this would be a modest one. Nevertheless, senators tend to respond to proposed changes to the rule book with declarations of horror and outrage. We can expect that tradition, at least, to be enthusiastically honored. A glance back at the arcane art of filibuster reform:

1913

The 17th Amendment is adopted, granting voters, rather than state legislatures, the power to elect senators.

1917

A 23-day filibuster against a proposal to arm merchant ships pushes President Woodrow Wilson over the edge. He calls a special session of the Senate and persuades the members to adopt a cloture rule that allows filibusters to be ended with the agreement of two-thirds of the Senate.

1949

The Senate decides that the cloture rule also applies to procedural motions, such as a motion to proceed.